[Assessment of precancerous states of the esophagus in dynamic observation].

One hundred and thirty six patients with chronic lesions of the esophagus and stomach were observed dynamically for a 5-year period (with the use of fibroesophagogastroscopy). Twelve patients showed the esophageal cancer development: in 7 of 86 patients with chronic esophagitis and in 5 of 15 patients with leukoplakia. A high incidence of leukoplakia transition into cancer allows its being referrred to an obligate precancer of the esophagus.